Lathe



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LATHE Filed March 20, 1947 9 Sheets-Sheet 4 INVENTORS Wasp/aBYTfiWJUZ/"W March 27, 1951 osc EI'AL 2,546,913

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"I: Z 1 .029 A546 3.97 1 8 345.022 5J5 HNE Z -.m7 $40 250 FEED 5 .ma ,9.005 I 8 L |55 5 D07 INVENTORS 5 l Z D06 6 p, 1 L, Wartrfydfi. @M/(m/March 27. 1951 A. TROSCH ET AL 2,546,913

LATHE Filed March 20, 1947 9 Sheets-Sheet 6 March 27, 1951 A. TROSCH ETAL LATHE 9 Sheets-Sheet '7 Filed March 20, 1947 ZNVENTORS {270.50% or (IA. TROSCH ET AL March 27, 1951 LATHE 9 Sheets-Sheet 8 Filed March 20,1947 March 27, 1951 A. TROSCH ET AL 2,546,913

LATHE Filed March 20, 1947 9 Sheets-Sheet 9 \WWHHHHHHHh 8 m 521 are 224a Patented Mar. 27, 1951 UNITED STATES rTsNT orrics LATHE Alfred'irosch, Brighton, and Worthy J. F. Forward, Rochester, N. 1., assignorsto Consolidated Machine Tool @orporation, Rochester, N. Y, a corpcrationof Delaware Application March 29, 1947, Serial No. '?36,058

8 Ciaims.

The present invention relates to machine tools and particularly tomachine tools of large size for doing heavy work. In a more specificaspect, the invention relates to large size lathes, such as are employedin turning, facing, and threading operations on the propeller shafts ofheavy marine drives, etc.

In a cutting operation on a lathe, the work is revolved on its axiswhile a relative feed is effected between the tool and the work. Forturning and boring and for cutting screw threads, the feed is lengthwiseof the work, while for a facing operation, the feed is transverse of thework.

The quality of finish of the work in a turning or facing operation, andthe pitch of the thread in a thread-cutting operation, are determined bythe distance which the tool moves for each revolution of the work.Accordingly, on general purpose lathes it is the practice to providefeed change gears whereby the rate of feed per revolution of the workcan be varied to suit the job which is to be out. Some metals are harderthan others; diameters vary considerably on difierent jobs; differenttypes of tools may be employed in cutting different types of Work. Forall these and other reasons it is also the practice on general purposelathes to provide speed change gears to vary the rotation of the workrelative to the tool. If the speed of rotation of the work is excessive,the tool will become dull in too short a time and the lathe cannot beoperated economically. For a thread-cutting operation, the work rotationhas to be in time with the lengthwise feed so that a thread of thedesired pitch may be cut, but for a turning or boring operation thetiming of the feed to the work rotation is not so critical. In lathes oflarge size it is therefore the practice to provide a feed screw and nutfor controlling the lengthwise feed of the carriage duringthreadcutting, but to use a pinion, or a pair of pinions, and a rack tofeed the carriage longitudinally during turning. Thus, the feed screw,which must be made most precise, is saved from unnecessary wear.

Heretofore, these large lathes have been constructed so that both thefeed screw and the feed pinion are driven in time with the rotation ofthe work spindle. Thus, the same set of change gears are in the trainfor driving the feed screw as for driving the feed pinion.

In machining a large work-piece, there may be several operations to beeffected on the lathe. The work may have to be turned to differentdiameters at different portions along its length, as to. provide journalbearings, a gear body, etc.; the ends of the gear body may have to befaced; and, in addition, the shaft may have to be threaded along partsof its length. It is customary on a large size lathe to perform all ofthese operations in a single set-up of the machine. For

the turning and facing operations faster feeds, however, can be employedthan in a threading operation. Hence, the operator of the machine isexpected to shift change gears between turning and threading operationsso that the machine can be run during each operation at the speed bestsuited to that operation.

For big work, the lathe required is a huge machine, long as well ashigh. Steps may have to be provided on the side of the machine, forinstance, so that the operator can have access to the work and the tool.In large size lathes as heretofore built, the speed and feed changegears have been placed together at one end of the machine, which meansthat they are quite a number of paces away from the normal position ofthe operator in observing the operation of the machine. It is burdensomefor the operator to walk back. and forth from operating position to thechange gear box, changing gears to suit the different types of work tobe done at different points along the length of the work-piece. Theoperator has to be careful, of course, to use the correct change gearsfora thread-cutting operation, for if the pitch of his thread is notright, the job has to be scrapped, but for a turning or facing operationthe change gears do not have to be so exact. The ratio of feed to workrotation affects the finish of the job, but within fairly wide, limitsthe important function of the feed change gears in a'turning operationis to govern tl speed of that operation. Therefore, an operator prone tolet the feed change gears, which he has selected for the thread-cuttingoperation on the job, govern the turning or facing operations, so thathe doesnt have to go back and to the change gear box to shift gears.This means that the turning operation is frequently performed at aslower speed than necessary, with the consequent loss of time inproduction. Moreover, it means that the feed screw is run unnecessarily,when the feed pinion and rack might be used, and as a result the screwis subjected to excessive wear, impairing the accuracy of the machine.

Another disadvantage of previous designs of large size lathes, evenwhere the operator is most careful about shifting change gears to suitdifferent phases of work to be done, is that the operator must stop themachine completely before he can effect shift of these gears. Hence, themachine has ordinarily to be stopped and started many times in thecourse of machining a particular piece of work. This again means loss ofproduction time.

One object of the presentinvention is to provide a lathe for large sizework in which the feed mechanism for turning, boring, and facingoperations is wholly independent of the feed mechanism for threading,and in which separate sets \i of change gears are provided for the twofeeds, so that the operator will be motivated to choose the proper feedfor each phase of the job.

A further object of the invention is to provide a large size lathe inwhich the feed for threading is so separated from the feeds for turning,boring, and facing that the. feed screw will only be employed duringthread-cutting, and this quite expensive and accurate part of themachine may have the maximum life.

Another object of the invention is to provide a large size lathe inwhich the feed change gears for turning and facing operations will bereadily accessible to the operator, so that he can easily shift gears toobtain the proper feed for any turning, boring, or facing operationwithout moving from his normal operating position.

A further object of the invention is to provide a lathe in which shiftfrom a turning or facing operation at one feed rate to a threadingoperation at a different feed rate, or vice versa, can be made withouthaving to stop the machine.

Another object of the invention is to provide a large size lathe havinga separate feed for turning, boring and facing from the feed forthreading, in which the feeds are so interlocked that one cannot beactuated. while the other is in operation or operable.

Another object of the invention is to provide a lathe having a feedmechanism for turning, boring, and facing operations with which analmost infinite. variety of such feeds may be obtained.

A. further object. of the invention is to provide a feed mechanism forturning and facing operations which is actuated by a variable speedmotor and with which a fine, medium, or coarse feed, as desired for aparticular job, can be obtained while effecting the operation at thefastest speed suitable to the job.

Still another object of the invention is to provide the operator with acombined chart and gauge from which he can quickly and accuratelydetermine from the speed of rotation of the work spindle and the linearfeed rate, what speed of motor and what set of feed change gears to useon a particular turning, boring, or facing operation.

Other objects of the invention will be apparent hereinafter from thespecification and from the recital of the appended claims.

In the drawings:

Fig. 1 is a side elevation of a lathe built according to one embodimentof this invention;

Fig. 2 is a fragmentary side elevation on an enlarged scale of a part ofthis lathe, showing particularly the feed drive for turning, boring, andfacing operations;

Fig. 3 is a fragmentary view on an enlarged scale illustrating theinterlock for the speed change gears of the work spindle drive;

Fig. 4 is a transverse sectional view through the machine on an enlargedscale;

Fig. 5 is a fragmentary sectional view on an enlarged scale, showingdetails of the drive to the feed pinions, the section being taken on theline 5-5 of Fig. 6;

Fig. 6 is a sectional view taken at right angles to the section of Fig.5, the section being taken on the line 6-6 of Fig. 5;

Fig. 7 is a fragmentary view, looking at the right hand side of theparts shown in Figs. 5 and 6, parts being broken away, and the part ofthe lathe bed being shown in section;

' Fig. 8 is a fragmentary sectional view taken on the line 88 of Fig. 6;

Fig. 9 is a fragmentary sectional view on the line 9-5 of Fig. 8,showing a detail of the mechanism for operating the nut which cooperateswith the lead screw;

Fig. 10 is a fragmentary sectional view on the line IE3H1 of Fig. 8,showing a further detail of this nut operating mechanism and showing thenut in open position;

Fig. 11 is a section on the line ll-H of Fig. 6;

Fig. 12 is a section on the line l2|2 of Fig. 6.;

Fig. 13 is a fragmentary sectional view on the line Iii-l3 of Fig. 5,looking at the back of the apron of the lathe carriage, showing thesplit nut, which cooperates with the lead screw, in open position;

Fig. 141s a fragmentary view, showing the split nut and the mechanismfor operating the same, with the nut in closed position;

Fig. 15 is a fragmentary sectional view on the line 65-!5 of Fig. 5,.showing the interlock between two of the shift rods which control theclutches of the turning feed change gear box;

Fig. 16 is a fragmentary view corresponding to Fig. 15, but showing theinterlock in operative position;

Fig. 1'7 is a fragmentary view, on a greatly enlarged scale, taken atright angles to the lathe bed and showing particularly the mounting, of

the operating levers which control the various.

clutches of the turning feed change gear box;

Fig. 1.8 is a plan view of the parts shown in Fig. 17, part of themechanism being broken away to show the feed screw and the gauge whichit actuates;

Fig. 19 is an elevational view of the combined chart and gauge which maybe provided to enable the operator to quickly determine what motor speedand feed change gears he should use in a particular turning, boring, orfacing operation;

Fig. 20 is a section on the line 29-40 of Fig. 19; and

Fig. 21 is a drive diagram of the machine.

The lathe illustrated in the drawings has, as have had prior lathes, afeed screw and nut for producing the longitudinal feed movement of. thecarriage during threading operations, and separate pinions and a rackfor producing the lengthwise feed motion of the carriage during a turn"ing or boring operation. As in previous types of lathes, also, the driveto the feed-screwis geared to the work spindle drive, and speed changegears are incorporated in the work spindle drive while feed changegears. are incorporated in the train of gearing which connects the workspindle with the lead screw, so that the feed screw may be driven inproper timed relation to the rotation of the work spindle to produce athread of the required pitch. In this machine, however, the feed pinionsare driven througha train of gearing completely separate from the drivesto the work spindle and feed screw, and. actuated by a motor separatefrom the. motor which drives the work spindleand feed: screw. This motoris a variable speed motor, preferably of the electronicallycontrolledtype with an extremely wide range of speeds. Change gears are providedbetween this motor and the feed pinions and by shifting clutches a fine,medium or coarse feed can be obtained at any motor speed. A safetyinterlock is provided between. the two feed. mechanisms so that thedrive to the feed screw cannot be engaged while the drive to the feedpinions is in engagement and vice versa.

The cross-feed drive for facing operations is actuated from this samevariable speed motor and through these same sets of change gears. Aseparate clutch is provided to permit engaging selectively either thelongitudinal or the crossfeed drive.

While the levers for shifting the speed change gears and the feed changegears of the feed screw drive are left, as in previous designs of heavylathes, at the headstock end of the machine where both can bemanipulated from the same position, the levers for shifting theclutches, that control the feed change gears of the feed pinion drive,the lever that controls the interlock between the feed screw and thefeed pinion drives, the controls for the variable speed motor of thefeed pinion drive, and the combined chart and gauge by which theoperator may determine what speed of the variable speed motor and whatset of change gears to use for a particular job, are all located at acentral point longitudinally of the machine where the operator caneasily manipulate or observe them, as the case may be, from oneposition.

Since normally the same pitch of thread is used, even though threads areto be cut at different points along a shaft or other workpiece, with themachine illustrated, the operator can set the feed change gears requiredfor threadcutting before he starts the machine, and thereafter he doesnot have to move from his central observing position during the wholeoperation of machining a particular job. When it becomes necessary toturn or face, he simply shifts the proper lever at his central operatingposition. Moreover, since separate sets of change gears are included inthe feed screw and rack drives, respectively, and since these drives areinterlocked, the operator does not have to stop the machine to shiftfrom a thread-cutting to a turning or facing operation, and vice versa.Hence the complete machining on a particular piece of work can beeffected. in the shortest possible time.

Referring now to the drawings by numerals of reference, 3!! denotes thebed of the machine, 3| designates the headstock and 32 the tailstock. Journalled in the headstock 3i is the work spindle $3. Secured to thisspindle, in any suitable manher is the face-plate 35, and mountedcoaxially of this spindle to project forwardly of the faceplate is thecenter 36.

The tailstock 32, which may be of any standard or suitable construction,carries the center 33,

. which is in axial alignment with the center 36 of the headstock. Thework W is adapted to be supported between these two centers. In theinstance shown, the face-plate 35 has secured to it by means of screws6| a plurality of chucking members 40. These members carry clamping jaws42 which engage the work so that it will rotate with the face-plate andwork spindle between the centers 36 and 38. V

In the drawings, the work, which is to be machined, is a shaft havingportions 45 and 46 that are'to be threaded, portions 4'! and 58 that areto be turned to one diameter, for instance, for hearing purposes, and aportion 50, which is to be turned to a greater diameter, for instance,to form the body portion of a gear. In addition, the surfaces 5| and 52of the portion require to be faced and the surfaces 53 and 54 of thebearing portions ll and 48, respectively, may also needto-be faced.

The tools "1. '(Figs. 1 and 4), which are to be used for the variousoperations, are adapted to be clamped in the usual manner to the toolpost 63 as by means of bars 60, screws El and nuts 62..

The tool post may be of standard construction and may be mounted, inconventional fashion for rectilinear adjustment on the compound slide orrest 65, the adjustment being effected in the usual manner by. a screwoperated by the handle 65. The compound slide is mounted for rectilinearadjustment on a table Ii! for adjustment in a direction at right anglesto the direction of adjustment of the tool slide 63, the adjustmentsbeing effected in the usual manner by means of a screw, such as screw1|. The table is mounted in the usual manner on a cross-slide 12 forangular adjustment thereon. This adjustment may be effected in anysuitable fashion, and after it has been completed, the table 10 may besecured to the cross-slide 12 by bolts 13. The cross-slide I2 ismounted, as usual, for rectilinear movement on the carriage E5 of thelathe in a direction at right angles to the direction of movement of thecarriage. The carriage i5 is adapted to slide on parallel longitudinalways 16 formed on the bed 3!! of the machine.

For a facing operation, the cross-slide I2 is actuated by screw .11 in amanner which will be described hereinafter in more detail. During aturning or a threading operation, the tool T is moved axially of thework by movement of the carriage 15. In each case, of course, the workrotates on its axis through rotation of the work spindle 33.

The work spindle is adapted to be driven from a motor Bil (Fig. 21)which may be mounted at any suitable point on the bed 30 or headstock3|. The armature shaft 8| of the motor has a pulley 82 secured to itthat drives a pulley 83 through a belt 86. The pulley 83 is keyed to ashaft 84 (Figs. 1. and 21). This shaft is journalled in any suitablemanner in the headstock 3|. It is splined at its inner end and hasslidably mounted thereon a spur pinion 85. The pinion 85 is adapted tobe moved axially on the shaft 84 by means of a shift lever 81 to engagethe pinion either with a spur gear 88 or a spur gear 39. The pinion isshown in full lines in Fig. 21 in engagement with gear 88, and in dottedlines at 85' in the position it occupies when in engagement with gear89.

The gear 88 is keyed or otherwise suitably secured to a shaft 90 whichis suitably journalled in the headstock 3|. The shaft 90 has a pinion 92slidably keyed to it. This pinion is adapted to mesh with an internalgear 93 which is secured to or formed integral with the face-plate 35.The gear 89 is keyed or otherwise fastened to the work spindle 33.

In one position, then, pinion 85 drives the faceplate 35 and workspindle 33 through the gear 88, shaft 90, pinion 92 and internal gear93. In its other position, pinion 85 drives the work Spindle 33 andface-plate 35 through the gear 89. Thus, by shifting the pinion 85, thework can be rotated at different speeds.

The shift lever B! is connected to the pinion 85. by a shaft 95 (Figs. 1and 3) and a lever arm 96. The shaft 95 is suitably journalled intheheadstock 3|. The shift lever 81 is secured to one end of this shaftwhile the lever arm 96 is secured to the other end thereof. The leverarm 96 carries a roller at its free end which is adapt- 3 ed to engagein a peripheral groove 98 formed in the hub of pinion 85.

When the pinion .85 is driving the work pindle 33 through the gear 5.9,i s nad abl ha e the pinion 9.2 in wi h n e na ee 3.- For this rea o ashi t ver w s erg s by of which the pin n 92 may e moved ax ally and censae me t w t he seer 53- Thi sh ft lever we s e -r a sh ft t! t t ha as r p n it inteera wi i This n h s i a a k L83 that is fastened to orside of a sleeve which is integral with pinion 5. 2 and which is d ptedt s ide ax ally a s f 5- t shaft 39 is splined so that, as alreadyindicated, pinion 92 will not rotate relative thereto. Pinion 52 isshown in full lines in Fig. 21 in engagement with internal gear 93, andin dotted lines in the position it occupies, when withdrawn axially r mmesh ith the nte nal sear.

To prevent the pinion 3.5 from being shifted into engagement with thegear 89 while the pinion 92 is in engagement with the gear an interlockis provided between the two shift levers 8? and me, This interlock(Figs. 1 and 3) c mprises a rod its, which has rack teeth I58 formed onone side adiacent one end. These teeth engage with a pin on H3? formedintegral w th th s a t 35, T od 65 ha a n t 138 in it adjacent its otherend and at the op.- pcsififi side from the rack teeth I35. Mountedbetween the rod i515 and the shaft 55 of 511' t lever ,8? is a lockingbar I it}. This bar has its opposite ends formed to conical shape asdenoted at HI and 512, re ectively. The end i ll is adapted to seat inthe notch H38 of har I95 and the nd 1 2 is ada d c sea in a c ic n ch fomed n t e shaft 95. The a is ada d to reci ca i a ide memb r He hat issecu ed to th h ad t l in th p s ion s own 3, the bar HQ loci cs theshaft .95 against Ila-ales. becauseits comi al end ll! id n th pe h ryof th rod 195 and its conical end H2 is eng a hu ch in the aft 55 hi i te n he pa t i e. rinicn 9. s in c .h i h the int na sear 331- When the8. withdrawn from n sh with. the int rnal th pin n and a e s a e m ed t9the left, but the rod 125 is grieved to the ri. t n h no ch 81 s .b eue'int s t-tr the conical end Hi of the jhar Hi3. Thus, the bar 120 candrop down, disengaging the end II? of the bar from the cooperating notchin the shaft 235. Then the shaft 95 is free to be rotated to shift thepinion 5 into engagement with the gear 89. The shift levers 8] and I853may he manipulated by grasping spring-pre sed knobs that are secured toe levers. These knob-s may travel in the alreuate slots Ii? and H8,respectively, provided on the side of the headstock 3i, and may helockedat opposite ends of their travel by engaging in the recesses I i5 andH6, respectively, is conventional practice.

For thr-ead-cutting, as already stated, the carriage i5 is movedlongitudinally of the bed 3 0 in time with the rotationcf 'hwcrksgt-indle -33. This movement is eifected hyrotation of the leadscrew E29 (Figs. 1 and 21). The t; n of which connects the work spindlewith the lead screw, will now be described. Since this gearing isconventional, it is only shown diagraminatlcally.

Keyed to (the wcrl; spindle s a sleeve lid with. which are fori edintegral .two J31 spar gears I22 and L23. gear [22 meshes with a spurpinion I 24, which is ,secured .to a shaf tion it meshes with ;a .,sp urgear I84.

8 2 th i uita y iev na l d i e h ds ek 3|.

Keyed to a shaft 530, that is jcurnalled in the headstock 3| inparallelism to the shaft I 25 and work spindle 33, is a spur pinion ISI.Thi pin: ion is adapted to slide on the shaft 3.13 and is adapted to bemeshed selectively with either the pinion I2 3 or the gear 123 to drivethe shaft 1 3.0 in opposite directions, respectively, from the workspindle ii The pinion 235 is adapted to be shifted axially bymanipulation of the lever I32 which is fastened to a shaft 133 that isjournalled in the headstock 3i This shaft has a lever arm I36 secur d toits other end which carries a roller that engages the peripheral grooveI35 formed in the hub of pinion I3 i.

Keyed to the shaft a spur gear 5M3. This with a spur gear sea that isintegral with a sleeve 5st ahicn is suitably jo n: nailed in theheadstock. to rotate about axis I43. integral with the sleeve I42 is asecond spur gear I413 which is of different tooth numher from the geariii. The M5 and i235. are adapted to mesh res-neon ely, with i 25 andE42. are formed integral with a or hub I ll' which rotates about axis I33 which is suitably jcurnalled in the headstock 3!. This sleeve orhubhas apee ripheral groove M53 formed in it wh' is adapted to be engagedby the roller of a shirt lever (not shown) so that the can he movedaxially to en age the gears $45 and 55 selectively with the gears iiiand I ii, respectively, to drive the shaft 2.43 at different speeds fromthe shaft lligi. The gear I415 meshes with a long-faced gear I513 whichrotates on an axis I 5!, and this gear meshes, in turn, with a gear E52which rotates on an axis I 53. The gear I52 meshes with a gear .254which rotates on an I 55.

Secnred to the shaft 55 is a .spur pinion I58. This pinion forms partsof a conventional feed change gear set, which .can be shifted by theshift lever LEI (Fig. l). The pinion IE9 meshes with a spur pinion i612which is rotatable on the axis [53 and which is mounted in conveni--tional manner to move axially with the pinion its K ed to a shaft 165,which is parallel to the shai O- I,5 5 and 563, are plurality of feedchange gears let to H3 inclusive, which difier in tooth number from oneanother. The gears I68 and i523 ,are adapted to he moved axially alongshaft 452 and to be swung about the axis of shaft I that the pinionWhile remaining in mesh with the pinion 1-53, may

simultaneously be en.-

.gaged. selectively with any oneof the feed change vone or other ,of thegears 1.15 or H5 can be connected to the shaft I88 to drive that shaftfrom shaft 5.65.

{Spill ed ,to the shaft 189 is a .spur gear I82. I83 denotes a gearwhich is splined to a shaft 138 that is axiallyaligned with shaft [f Thegear I32 is slidable on shaft I 80.

In one posi- The-gear 18,3 meshes with ,a ,spur pinion 185. The gear 84and pinion I are integral with asleeve ,l 8 6.

.18 a bevel gear 233.

The gear I82 has a hub portion integral with it which is provided with aperipheral slot I31 and which has face clutch teeth l88 formed on oneend thereof. These clutch teeth may be engaged with complementary faceclutch teeth I89 formed on the hub of the gear I83. When the gear I82 isin the position shown in Fig. 21, the drive from shaft I83 is throughgear I82, gear I84, pinion I85 and gear I83 to shaft I99. When the gearI82 is shifted axially to the right, however, to engage clutch teeth I88and I39, then the shaft I8?) is directly coupled to the shaft I90.

Secured to the shaft I90 is a spur pinion I92 which meshes with a spurgear I93 that is secured to the lead screw I20.

The lead screw I22 is adapted to engage with a split nut, the two partsof which are designated 290 and 200, respectively (Figs. 7, 8, l3 and14). Each part of the nut is formed-with a dovetailed guide portion,denoted at ZBI and 2M, respectively. These dove-tailed portions arevadapted to slide in a slot or guide-way 202 (Fig.

'7) formed in the apron 203 of the carriage I5.

The split nut is adapted to be opened or closed, to engage or disengagethe screw I20, by manipulation of an operating lever 205 (Figs. 18 and2) This lever is secured to a shaft 203 which is suitably journalled ina column 288 that is mounted on the carriage 15 to travel with thecarriage. Pivotally connected to the lower end of the shaft 206 as bymeans of a pin 29?. (Fig. 1'7) is a link 2H3 (Figs. 2 and 17). This linkis pivotally connected at its opposite end by means of pin 2II with abar 2 2. The bar 2I2 has rack teeth 2I3 (Fig. 9) formed on one sidethereof which engage with the teeth of a pinion 2I l (Figs. 2, 8, and 9)that is secured to or integral with a shaft 2 I 5.

The shaft 255 has a disc 2I6 (Figs. 8, l0, and 7) integral with it. Tothis disc there are connected by pirns 2i? and 2;? two arcuate linkmembers 2&3 and 258. in turn connected by pins 2E9 and 2I9,respectively, to the dove-tailed portions 2iiI and 2M,

respectively, of the split nut members 200 and 230, respectively. Thus,by moving handle 2B5 (Figs. 2 and 18) in one or the other direction, thesplit nut can be opened or closed. It is shown in open position in Figs.7, l0, and 13 and in closed position in Fig. 14. The split nut must beclosed when a thread is to be cut on the work and the feed screw is todrive the carriage. The split nut is open or disengaged when the work isto be turned, faced, or bored.

The drive for facing, turning or boring is actuated by a variable speedmotor 225 which is mounted in any suitable manner on the apron 2533 ofthe carriage (Figs. 1, 2, 5, 6, and 21). The armature shaft 225 of thismotor is connected by a suitable coupling 22! with a shaft 228 that issuitably journalled in the apron 203. There is a worm 229 integral withthis shaft. This worm meshes with a worm wheel 233 that is journalled ona stud 23I which is secured against rotation in the apron 283. Integralwith the worm wheel This meshes with a bevel gear 234 which isrotatably' mounted on a shaft 233 that is suitably journalled in theapron.

plementary face clutch teeth formed on one end of a sleeve member 222,which is splined or keyed These link members are The shaft 223 also hasa spur gear 235 secured These teeth are adapted to be engaged with comtothe shaft 235 and is axially slidable thereon. Sleeve member 242 hasother face clutch teeth formed on its opposite end which are adapted toengage with face clutch teeth formed on the confronting face of thebevel gear 234. Thus, by shifting the sleeve member 242 into engagementeither with the clutch teeth of the gear 238 or with clutch teeth of thegear 234, the shaft 235 may be driven selectively from the shaft 223through spur gears 235 and 238 or through worm 223, worm wheel 23 bevelgear 233 and bevel gear 235. In this way, the shaft 235 may be drivenselectively at two different speeds from the shaft 228. When the sleeve242 is in neutral position, th shaft 235 does not rotate.

The sleeve 2 52 is adapted to be shifted axially by a lever 250 (Figs.2, 17, and 18) which is secured to a vertical shaft 25I that is suitablyjournalled in the column Fastened to the low er end of this shaft is anarm 253 which is connected by a pin 254 to a link member 255 which inturn is connected by a pin 25% with a rod 258.

The rod 253 (Figs. 2, l2 and 5) has an arm 233 secured to it by a splitclamp, This arm ter1nihates at its free end in a yoke which engages inthe peripheral groove 282 of the sleeve 232. Thus, on movement of thelever 259 in one direction or the other, the sleeve 2 12 can be shiftedin one direction or the other to connect operatively either the gear 233or the gear 234 to the shaft 235.

There is a worm 265 (Figs. 5 and 21) integral with or keyed to the shaft235. This worm meshes with a worm wheel 2% (Figs. 8, l2 and 21). Theworm wheel is keyed to a sleeve 26? (Fig. 8) which is integral with abevel gear 262. The sleeve258 is journalled. on a stud 269; which issuitably secured in the apron 2E3 against ro tation. The bevel gear 238meshes with. a bevel gear Zl'il that is integral with a sleeve or hub i.The sleeve or hub 215 is rotatably mounted on a shaft 2'82 which issuitably journalled in the apron 233. The spur gear 339 is alsorotatably mounted on the shaft 2'52.

Keyed or splined to the shaft 2'52 and mounted to slide axially thereona sleeve 2112 which has face clutch teeth formed on both its ends thatare adapted to be engaged selectively with complementary face clutchteeth formed on the confronting ends of the hub Z'ii of bevel gear 2'63and the hub 2?5 of spur gear 239, respectively. Thus, if the sleeve 22?(Figs. 5 and 21) is in neutral position, the shaft 2752 may be drivenfrom shaft 223 through spur gears 236, 235 and 239 by shifting sleeve214 to the right (Figs. 8 and 21) to engage the face clutch teeth formedat the righthand end of this sleeve with the face clutch teeth formed onthe inner face of the hub of spur gear 233. On the other hand, bshifting the sleeve 262 to the left, and by shifting the sleeve 2E4 tothe left to engage the clutch teeth formed on the left-hand end of thissleeve with the clutch teeth formed on the right-hand end of hub 21! ofbevel gear 213, the shaft 212 may be driven from the shaft 228 throughthe Worm. 229, worm wheel 23%, bevel gear bevel gear 235, shaft 235,worm 255, worm wheel bevel gear 223 and bevel gear Elli (Figs. 5, 8, 12and El).

Shift of sleeve 21 2 is effected from a lever 263 (Figs. 2 and 18) whichhas a split clamp connection with a shaft 232 that is suitablyjournalled in the upright 20%. The shaft 58I has an arm 285 (Fig. 17)secured to it at its lower end by a split clamp connection. This arm isconnected by a "a time,

pin 23% with a link 235 which is pivotally connected by means of a pin25? (Fig. 18) with a rod 288. The rod 283 is slidably mounted in theapron 2G3 and has a yoke member 289 (Figs. 8 and 12) secured to it by asplit clamp connection. The free end of this yoke member is adapted toengage in the peripheral groove 2% of sleeve 214, so that when the lever28% is moved in one direc tion or the other, the sleeve 274 is shiftedaxially on the shaft 2H2 to connect, selectively, either spur gear 239or bevel gear with that shaft.

There is a worm 295 keyed to or integral with the shaft 232. This wormmeshes with a worm wheel 2% (Figs. 5, 11, and 21), that is keyed toshaft 2%! which is suitably journalled in the apron 253. The shaft 29?has a sleeve 298 mounted on it for axial sliding movement. The

sleeve has an external spur gear 538% and an internal gear 55G! integralwith it. The internal gear 35! is adapted, in one axial position ofsleeve 293, to engage a wide-faced spur pinion 3&2 which is journallcdon the shaft 29?. The eX- ternal gear 3% is adapted, in another positionof sleeve 2%, to mesh with a pinion 5- i 5.

The pinion 3&2 is a long-faced pinion, as stated, and is adapted to meshat opposite sides with two spur gears 35 i and 385 that are keyed to twoparallel shafts 3% and 301, respectively. These shafts are suitablyjournalled in the apron 2E3. Integral with the shafts and 397,respectively, are spur pinions 393 and 339, respectively, that mesh witha rack 226 (Figs. 1, 2, i, '7, l7 and 21) at spaced points therealong.The rack 226 is fastened to the bed 36 of the machine by screws em. Whenthe sleeve 2% is shifted to the position where internal gear 30! mesheswith spur pinion 382, then carriage is will be driven by the pinions 383and 3139 rotating on the fixed rack 228.

The spur gear 3H5, with which the spur gear 35353 is adapted to mesh inthe other position of sleeve 298, is secured to a shaft 3H5 (Figs. 2, 4and 21) that is suitably journalled in carriage F5. The gear 3i5 mesheswith a spur pinion SIB which is secured to the screw shaft ii thatefiects the crosswise feed of the tool. This shaft threads into 3, nut3!! that is fastened by screws SIS to cross-slide 72 (Fig. 4). When thesleeve 29% is in position, therefore, where the spur gear engages andmeshes with spur gear 315, crcsswise feed of the tool is eiiected whilelengthwise movement of the carriage is stopped.

For shifting the sleeve 2%, a lever 320 (Figs. 2 and 18) is provided.This lever is secured by a split clamp connection to a vertical shaft532; which is suitably journalled in the upright This shaft has a bevelgear 322 Fig. 17) secured to its lower end which meshes with a bevelgear 323 that is keyed to a shaft 326. The shaft 324 ias a yoke member325 (Figs. 6 and 11) fastened to it whose ends carry rollers that engagein a peripheral groove 326 (Fig. 5) formed in the sleeve 298. Bymovinglever 32B in one direction or the other, then, internal gear 3! may bemeshed with pinion 5-582 to produce longitudinal feed or" carriage 15for turning or boring, or ere ternal gear 338 may be meshed with gear toproduce crosswise feed of slide 72 for facing.

To avoid having the split nut in engagement with the lead screw 528 whenthe internal gear SM is in mesh with pinion 3E2, an interlock isprovided between shaft 206 (Fig. 13) which con.- trols the shifting ofrod 2i2 (Figs. 8 9), shaf 321 (Fig. 18-) which controls Shifting; ofsleeve 298 (Figs. 5 and 11). The shaft 263 l2 18) formed in its psiphery 33! formed on upright 2B8 mounted a pin 332. This conical. Theshaft otherwise fastened has a notch 5339 and is an arm in whichslidably has both its ends made am has an arm 333 keyed or to it justabove bevel gear 322 (Fig. 2). This arm has a notch 33 formed centrallyin its periphery.

In the position shown in Fig. 18, the lever 328 is locked againstmovement, one end of the pin being engaged in the notch 33 3 or" arm 333sengaged from gear 315 and gear 36! from pinion 3592, while the lever235 .tated to open or close the split nut lead screw 52%.

In the posi ion of lever F2 35 shown in 13, the split hit is with thelead screw I29 the drive to the carriage T5 is through the nut and leadscrew as is required for threadcutting. Plates 2337 and attached tocolumn below the lovers 28 33, and respectively, be provided withdesignations, as shown in 18, to enable the operatcr properly to adjustthe different levers for the dilerent operations which he wishesperformed on the machine.

' the lever 28% is rotated to the right from on shown in Fig. 18, thatis, to a position 'nd 335 of pin 332 engages in notch split nut will beopened through operation of the 'hanism shown in Figs. 8, 9, and 7.0,and the lever 32% can moved either to the right or left from the neutralposition shown in 18. In either direction of its movement, the pin willride on the periphery of plate e it engages at its opposite end in the"daft 266. Thus, through the int: look, a e is had that the split nut istl-e is .d screw i2 3 cannot drive carri .gc w ver is in position toengage either the or crosswise feed mechanism.

When. is i shifted to the left from the s Fig. 18, the gear 355 will bewith the gear 315 and crossohtained, while when lever 32!} is moved tothe right from the position shown in Fig. 13, the gear 3% is moved intomesh with pinion so that turning or boring can be accomplished. Thespeed at which turning, boror cross-feed is effected will depend on thepositions of levers ESE-and 23% as will be described furtherhereinafter. It is to be noted that it is only by bringing the twolevers 2W5 and 320 to their neutral positions that one or the other canbe mote Thus, an absolute interlock is provided between the lead screwand the pinion and rack drive so that one or the other may be engagedbut not both. Further than this, through his interlock the pinion driveto the feed rack r the cross feed drive may be engaged, when e leaddrive is disengaged, but not both tiltaneously.

The rate at which cross-feed, turning, or borin': is effected will asstated above, upon the positions of levers 25 3 and 286 for thesecontrol, respectively, the axially movable sleeves 2 32 (Figs. 5 and 21)and 274 (Figs. 8 and 21). the levers will be so positioned hat he sleeve2&2 connects bevel gear 284 with and the sleeve 2'14 connects bevel gearshe. it 2i2. Then the drive is from shaft through worm worm wheel 236,bevel Fine Feed. 'rates obtainable by different settings of levers 2502%, bevel gears 258 and 2'10, worm 2.35 and worm wheel 293 to shaft 291.For coarse feed, sleeve 252 will be over to the right and so will sleeve21 so that the drive will be from shaft 223 through spur gears 236, 233and 239, shaft 272, worm 295 and worm wheel 2% to shaft 291.

The rods 258 and 288 (Fig. 12) which are actuated by these levers areinterlocked so that shaft 212 can b driven at any one time at only onefeed rate, namely, for fine, medium or coarse feed, respectively. Theinterlock between shift rods 253 and 288 is shown in Figs. 15 and 16. Itcomprises a pin 331 beveled on both ends. Shift rods 258 and 233 havenotches 33S and 339, re-

spectively in which opposite ends, respectively, of this pin are adaptedto engage. In Fig. 15 both rods are shown in neutral position, andeither one is free to be moved. Fig. 16 shows the rod 288 locked againstmovement, the lower end of pin 33! engaging in the notch 339 of rod 288and the upper end of pin 331' riding on the periphery of rod 2522. Rod258 has been shifted to the right from the position shown in 15, aswould be the case if sleeve 2A2 were shifted to connect spur gear 238with shaft 235.

While the shift rods 2% and 253 rates of feed during turning, boring, orfacing, the actual speed of these operations is controlled by the speedof motor 225. indicated a variable speed motor preferably of theelectronic type and may have as wide aspeed variation as from 15 to 1500R. P. M. Its speed and direction can be controlled by suitable electriccontrols including start and step and reverse 1 buttons and a rheostator potentiometer control button shown more or less diagrammatically at365 in Fig. 1'7. These are mounted on an upright 365 where they areaccessible to the operator as he stands on the carriage H in position tooperate the several levers 205, 256, 323 and 280. Because of the size ofthe machine, steps 36!! are provided so that the operator can readilyclimb up onto or down oil of the saddle or operating platform 362. 363and 288 are secured to carriage T5 to travel therewith.

For the assistance of the operator in determining what speed to use forthe motor 225 and what lever settings to employ, in turning, facing orboring a particular job or a particular part 7 of the work, a chart 3'40may be provided on the machine like that shown in Figs. 19 and 20. Onthe left-hand side of this chart are graduations showing various spindlespeeds obtainable on the machine. In the next column are simply thedesignations "Coarse Feed, Medium Feed, and These denote the differentfeed and 283. Th next column contains the feed rheostat settings foreach position of the control levers. The right-hand column contains thefeed in inches per revolution.

The chart may be placed on a heavy bronze or plastic plaque and has twolongitudinal slots 3M and 342 formed therein. Mounted on the of thechart and secured thereto by studs 343 is a transparent bar This bar hasa line red line 345 scribed on it. By selecting the spindle speed andthe desired feed in inches per revolucontrol the This is as already Thesteps 3% like uprights use for levers 255i and 23d and what setting toemploy on the rheostat which controls motor 225. A coil spring 34! oneach of the studs 343, which is interposed between a washer 358 and thenuts 349, serves to hold the bar 345 in any adjusted position.

A tachometer 352 (Fig. 1) may be provided in order that the operator mayreadily read the spindle speeds. This may be driven in any suitablemanner from the work spindle 33 as by means of the gear 353. Thistachometer may be of any usual or suitable construction.

The chart 3&6] itself will bemounted preferably on uprights 355 (Figs. 4and 17) so that it will be in position where it can readily be read bythe operator as he adjusts the various shift levers.

An indicator 3151 (Figs. 1'? and 18) is provided to enable the operatorto determine the exact relationship of the tool longitudinally of thework at any time. This indicator may be of any standard construction andis actuated by a pinion 31! which meshes with the lead screw 52% andwhich is secured to the carriage 15. The indicator 370 is mounted onthis" housing. As the carriage moves along the machine, the pinion 3will roll on the lead screw I23 and actuate the indicator to denote howfar the tool has moved axially along the work at any particular stage ofthe operation.

The tailstock 32 (Fig. 1) may be adjusted axially along the bed 30 tomove center 38 into and out of operative relation with the work. Thisadjustment may be effected in conventional manner by actuation of themotor 3% (Figs. 1 and 21) which is mounted on the tailstoclr whichdrives through the worm 33! and worm wheel 382, the pinion 383 whichmeshes with a spur gear 384 that is secured to a shaft 385 which carriesa pinion 386 that meshes with the raclr 225}. The tailstock may be alsoadjusted crosswise by a screw 392 which is journalled in the tailstock32 and which threads into a nut carried by the supporting base 390.Bolts 333 serve to secure the headstock to the bed in any adjustedposition.

The construction and operation of the machine have been described insuch detail that they need only be summed up briefly now.

For thread-cutting the split nut 200-200 is engaged with the lead screw1'29, and the work spindle 33 and lead screw 4253 are driven from motor88' in the proper timed relation to produce a thread of the desiredpitch through the train of gearing shown in Fig. 21 and which includessuitable feed change gears. Drive of the carriage 15 through the pinions308 and 3139 and rack 220 and drive of cross-slide 12 through screw 1'!are both prevented at this time through the interlock (Fig. 18) betweenlever 285, that controls the opening and closing of the split nut, andlever 32!] that controls the position of sleeve When it is desired toface or turn or bore, lever 235 is shifted to the right from theposition shown in Fig. 18, to open the split nut, and lever 32s isshifted either to the left or the right. Opening of the split nutdisengages the carriage feed through feed screw I20, and shifting oflever 32!! to right or left causes the carriage to be driven from motor225. Thus during facing, turning, or boring, the work spindle 33 isstill to mesh with pinion 362.

drivenfrom motor 88, but the carriage i is driven from motor 225, whileduring threadcutting, both work spindle 33 and carriage are driven frommotor St. For facing, lever 32!! is shifted to the left to cause gear309 to mesh with gear 3E5. For boring or turning, lever 320 is shiftedto the right to cause internal gear 35! The rate of feed during facing,turning, or boring, is determined by the settings of levers 250 and 286which control the positions of sleeves 24-2 and 274. The speed ofoperation during facing, turning, or boring is determined by the settingof the rheostat which controls motor 225. The tool may be positioned, ofcourse, for facing operations at the correct angle to the work axis byadjustment of the table 19 or the cross-slide I2.

It will be seen, then, that a machine has been provided on which shiftfrom thread-cutting to turning, boring or facing, or vice versa, can beeffected instantaneously without stopping the machine; that turning,boring, and facing opera tions can be performed at the highest,production speed; that controls for the several operations are mountedso that the operator need not leave his operating position to effectshift from one operation to another or to vary the rate and speed ofturning, boring, or facing operations; and that through provision ofsuitable interlocks, safe operation at all times is insured.

While the invention has been described in connection with a lathe, it isapplicable to other types of machine tools, also. In fact, while theinvention has been described in connection with a particular embodimentthereof, it is capable of further modification, and this application isintended to cover any adaptations, uses, or modivfications of theinvention following, in general, the principles of the invention andincluding such departures from the present disclosure as come withinknown or customary practice in the art to which the invention pertainsand as may be applied to the essential features hereinbefore set forthand as fall within the scope of the invention or the limits of theappended claims.

Having "thus described our invention, what we claim is:

1. In a machine of the character described, a bed, a work spindlejournalled in the bed, a carriage mcunted on the bed for movementlongitudinally of the work spindle, a slide mounted on the carriage formovement transversely of the carriage, a tool mounted on the slide,means comprising a motor and set of change gearing for rotating the workspindle, means comprising a spli -nut, which is connected to thecarriage, and a screw, that is rotatable therein, for moving thecarriage, means for opening and closing the nut, a train of gearing, inwhich change gears are incorporated, for driving the screw in time withthe work spindle, a shiftable member for selectively connecting ordisconnecting said train of gearing with the work spindle, meansoperable to drive the carriage independently of the lead screw and nutduring rotation of the workspindle,

means operable to actuate the slide, means for actuating the twolast-named means comprising a variable speed motor and a plurality ofselectively operable sets of gears of different ratio, respectively,driven by said motor, shiftable means for selectively connecting thelast-named actuating means with the means for actuating the carriage orthe means for actuating the slide, shiftable means for selectivelydetermining which set of gears is to be operable in the said last-namedactuating means, and means for interlocking the first-named shiftablemeanswith the means for opening and closing the nut.

2. In a machine of the character described, a bed, a work spindlejournalled in the bed, a carriage mounted on the bed for movementlongitudinally of the work spindle, a slide mounted on the carriage formovement transversely of the carriage, a tool mounted on the slide,means comprising a motor and set of change gears for rotating the workspindle, means comprising a split-nut, which is connected to thecarriage, and a screw, that is rotatable therein, for moving thecarriage, means for opening and closing the nut, a train of gearing, inwhich change gears are incorporated, for driving the screw in time withthe work spindle, a shiftable member for selectively connecting ordisconnecting said train of gearing with the work spindle, a shaft, aplurality of sets of gears for selectively driving said shaft, avariable speed motor, means shiftable to connect said sets of gearsselectively with said motor, means shiftable to connect said shaftselectively with said carriage or with said slide to actuate carriage orslide, and means preventing connection of the shaft with the carriage orslide while the split-nut is closed.

3. In a machine of the character described, a bed, a work spindlejournalled in the bed, a carriage mounted on the bed for movementlongitudinally of the work spindle, a slide mounted on the carriage formovement transversely of the carriage, a tool mounted on the slide,means for rotating the work spindle, means comprising a split-nut, whichis connected to the carriage, and a crew, that is rotatable therein, formoving the carriage, a lever for opening and closing said nut, a trainof gearing including change gears for driving the screw from the workspindle in time therewith, a shiftable member for selectively connectingor disconnecting said train of gearing to the work spindle, a shaft, aplurality of sets of gears for selectively driving said shaft, avariable speed motor, a plurality of shiftable clutches for selectivelyconnecting the sets of gears operatively with said motor and shaft,levers for actuating said clutches, means shiftable to connect saidshaft selectively with the carriage or with the slid-e to actuatecarriage or slide, a lever for actuating said shiftable means, and meansfor preventing connection of the shaft with the carriage or slide whilethe split-nut is closed, all of said levers being located adjacent oneanother to be accessible to the operator in one position.

4. In a machine of the character described, a bed, a work spindlejournaled in the bed, a carriage slidable on the bed axially of the workspindle, a motor and selectively connectable change gears for drivingthe work spindle at different speeds, a screw and a split nut foractuating the carriage, a train of gearing including change gears fordriving aid screw at different speeds, shiftable means for connecting ordisconnecting said train of gearing to the work spindle, and separatemeans for actuating said carriage during rotation of the work spindlewhen the screw and nut are disconnected from the work spindle comprisinga, rack, which is secured to the bed, and a pinion meshing with saidrack and journaled in said carriage, a variable speed motor mounted onsaid carriage, a second train of gearing including a plurality ofselectively connectable change gears, for unidirectionally driving saidpinion at selectively different speeds from said variable speed motor,and means for selectively connecting said change gears in said secondtrain of gearing, and means preventing rotation of the pinion while thenut is engaged with the screw and vice versa.

5. In a machine of the charact r described, a bed, a work spindlejournaled in the bed, a carriage slidable on the bed axially of the workspindle, a nut, which is secured to the carriage, and a screw threadinginto said nut for actuating the carriage, a slide mounted on thecarriage for movement transvers ly of the work spindle, a tool mountedon said slide, a motor and a train of gearing including change gears forrotating the work spindle, a train of gearing including change gears forrotating said screw, a shiftable member for selectively connecting ordisconnecting the s cond-named train of gearing to the work spindle, arack secured to the carriage, a pinion meshing therewith, a nut securedto the slide, a screw threading therein, a variable speed motor, a trainof gearing including change gears driven by said motor, means forselectively connecting said last-named train of gearing to the pinion orto the last-named screw, and means for preventing connection of thelast-named train'of gearing to either the pinion or the lastnamed screwwhen the second-named train of gearing is connected to the work spindle.

6. In a machine of the character described, a bed, a work spindlejournaled in the bed, a tool-supporting carriage mounted on the bed formovement longitudinally of the work spindle, means comprising a motorand a set of change gears for rotating the work spindle, meanscomprising a split-nut, which is connected to the carriage, a screw,that is rotatable in said splitnut, and a train of gearing, in whichchange gears are incorporated. for driving the screw in time with therotation of the work spindle, means for opening and closin saidsplit-nut, a shiftable clutch for connecting or disconnecting said trainof gearing with said work spindle, separate mean for driving saidcarriage independently of said lead screw and split-nut during rotationof the work spindle comprising a rack which is secured to said bed, apinion meshing with said rack and journaled in said carriage, a variablespeed motor, a plurality of difierent sets of gears selectivelycouplable to said variable speed motor and said pinion to transmitunidirectional power at selectively different speeds from said variablespeed motor to said pinion, said different set of gears beinrespectively, of different ratio, shiftable means for selectivelycoupling said sets of change gears with said variable speed motor andsaid pinion, and interlock means preventing transmission of powerbetween said variable speed motor and said pinion when said split-nut isengaged with said feed screw. and said interlock means including meanspreventing closing of said splitnut when said pinion is coupled to saidvariable speed motor.

'7.'In a machine of the character described, a bed, a work spindlejournaled in the bed, a carriage mounted on the bed for movementlongitudinally of the work spindle, a slide mounted on the carriage formovement transversely of the carriage, a tool mounted on the slide,means for rotating the work spindle, means comprising a split-nut, whichis connected to the carriage, and a screw, that is rotatable in the nut,for moving said carriage. a train of gearing for driving said screw fromthe Work spindle in time with the rotation of the work spindle, ashiftable member for selectively connecting or disconnecting said trainof gearing to or from said work spindle, separate means for selectivelymoving said carriage or said slide while the work spindle is beingdriven from said spindle-rotating means and while said train of gearingis disconnected from the work spindle comprising a variable speed motorwhich is mounted on the carriage, and a second train of gearing,including a plurality of selectively-operable gear sets, which isadapted to be driven by said variable speed motor, means for selectivelyconnecting any of said gear sets of said second train of gearing to saidcarriage or to said slide for selective speeds in a single direction,means for opening and closing said split-nut, and means for interlockingthe two last named means so that the nut cannot be closed while saidsecond train of gearing is operatively connected to either the carriageor the slide, and vice-versa, preventing transmission of power from saidvariable speed motor to either the carriage or the slide when the nut isclosed.

8. In a machine of the character described, a bed, a work spindlejournaled in the bed, a toolsup-po-rting carriage mounted on the bed formovement longitudinally of the work spindle, means comprising a motorand a set of change gears for rotating the work spindle, meanscomprising a split-nut, which is connected to the carriage, a screw,that is rotatable in said splitnut, and a train of gearing, in whichchange gears are incorporated, for driving the screw in time with therotation of the work spindle, a shiftable clutch for connecting ordisconnecting said train of gearing with said work spindle, separatemeans for driving said carriage independently of said screw andsplit-nut during rotation of the work spindle comprising a rack which issecured to said bed, a pinion meshing with said rack and journaled insaid carriage, a variable speed motor mounted on said carriage, a shaft,a plurality of difierent sets of gears selectively couplable to saidvariable speed motor and said shaft to transmit power from said variablespeed motor to said shaft, said different sets of gears being,respectively, of different ratio, a plurality of shiftable clutches forselectively coup ing the different sets of gears with said variablespeed motor and said shaft, levers for actuatin said clutches. meansshiftable to connect and disconnect said shaft and said pinion, a leverfor actuating said last-named shiftable means, means preventingconnection of said shaft with said pinion while said split-nut is closedand vice-versa, and a lever controlling opening and closing of saidsplit nut, all of said levers being located adjacent one another to beaccessible to the Operator in one position.

ALFRED TROSCH.

WORTHY J. F. FORWARD.

REFERENCES CITED The following references are of record in the idle ofthis patent:

UNITED STATES PATENTS

